US8331744B2 - Optical switch - Google Patents

Optical switch Download PDF

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Publication number
US8331744B2
US8331744B2 US11/940,476 US94047607A US8331744B2 US 8331744 B2 US8331744 B2 US 8331744B2 US 94047607 A US94047607 A US 94047607A US 8331744 B2 US8331744 B2 US 8331744B2
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optical
light beam
output port
reflected light
switch
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US20100284648A1 (en
Inventor
Hiroyuki Furukawa
Nobuhiro Fukushima
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Fujitsu Ltd
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Fujitsu Ltd
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/35—Optical coupling means having switching means
    • G02B6/354—Switching arrangements, i.e. number of input/output ports and interconnection types
    • G02B6/356—Switching arrangements, i.e. number of input/output ports and interconnection types in an optical cross-connect device, e.g. routing and switching aspects of interconnecting different paths propagating different wavelengths to (re)configure the various input and output links
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/35—Optical coupling means having switching means
    • G02B6/3586—Control or adjustment details, e.g. calibrating
    • G02B6/359—Control or adjustment details, e.g. calibrating of the position of the moving element itself during switching, i.e. without monitoring the switched beams
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
    • G02B6/29379—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device
    • G02B6/2938—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device for multiplexing or demultiplexing, i.e. combining or separating wavelengths, e.g. 1xN, NxM
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/35—Optical coupling means having switching means
    • G02B6/351—Optical coupling means having switching means involving stationary waveguides with moving interposed optical elements
    • G02B6/3512—Optical coupling means having switching means involving stationary waveguides with moving interposed optical elements the optical element being reflective, e.g. mirror
    • G02B6/3518—Optical coupling means having switching means involving stationary waveguides with moving interposed optical elements the optical element being reflective, e.g. mirror the reflective optical element being an intrinsic part of a MEMS device, i.e. fabricated together with the MEMS device
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/35—Optical coupling means having switching means
    • G02B6/354—Switching arrangements, i.e. number of input/output ports and interconnection types
    • G02B6/3544—2D constellations, i.e. with switching elements and switched beams located in a plane
    • G02B6/3548—1xN switch, i.e. one input and a selectable single output of N possible outputs
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/35—Optical coupling means having switching means
    • G02B6/3586—Control or adjustment details, e.g. calibrating
    • G02B6/3588—Control or adjustment details, e.g. calibrating of the processed beams, i.e. controlling during switching of orientation, alignment, or beam propagation properties such as intensity, size or shape

Definitions

  • the present invention relates to an optical switch, and in particular, the invention relates to an optical switch suitable for use as a wavelength-selective switch applied to an optical add/drop unit in a optical communication system.
  • wavelength multiplex OADM Optical Add Drop Multiplexer
  • FIG. 19 shows an example of a construction of wavelength multiplex OADM node.
  • a wavelength multiplex OADM (OADM device) 100 includes: a pre-amplifier 101 ; a splitter unit 102 which splits light from the pre-amplifier 101 into two; an wavelength-selective optical switch 103 for dropping which selectively drops light of an arbitrary wavelength channel of one of the light beams having been split by the splitter unit 102 ; an wavelength-selective optical switch 104 for adding which inserts light of a wavelength channel for add of the other light beam having been split by the splitter unit 102 ; and a post-amplifier 105 .
  • the wavelength-selective switches 103 and 104 which are for drop and add, respectively, are constructed in such a manner that multiple wavelength-selective optical switches in a cascade form. Accordingly, since the wavelength multiplex OADM 100 having the construction shown in FIG. 19 has advantages that the load, such as work of adding of channels corresponding to the number of wavelengths and port connection work, etc., is small, it is considered that it will become one of the main streams of node constructions in wavelength multiplexing optical transmission systems from then on.
  • FIG. 20 and FIG. 21 show examples of an abbreviated construction of the wavelength selective optical switch 110 ( 103 and 104 ) for use in add and drop in the above-described wavelength multiplex OADM 100 .
  • FIG. 20 is an upper view of the diagrammatic construction of the wavelength-selective optical switch 110 ( 103 and 104 ) which is used for add and drop
  • FIG. 21 is an front view.
  • the wavelength-selective optical switch 110 includes: collimators 111 which attempt to performing optical coupling between input and output optical fiber, which function as transmission paths; an optical splitter element 112 which splits parallel light from the collimator 111 ; a light-gathering lens 113 ; and a movable mirror array 114 .
  • the construction example shows that the input port 1 corresponds to the output port 2 , input and output paths can be inverted and the output port 1 can correspond to the input port 2 .
  • mirror devices 114 a are arranged in a form of an array (here, one row along with the X axis) so that reflection surface angles with respect to the X axis are individually set for mirror light (here, ⁇ 1 through ⁇ 5 ) split by the optical splitter element 112 .
  • each mirror device 114 a is supported in such a manner that it is individually rotatable with respect to the X axis and the Y axis.
  • an ODAM device using a wavelength selective switch is designed to be upgraded to have several tens of channels in consideration to increase in traffic in future in the optical transmission system. Normally, when the system is initially introduced, service generally starts with a small number of channels. In this case, the number of channels not in operation is relatively large.
  • Such standby channels not in operation are shuttered in a shutter movement region in an optical switch to remove natural radiation light (ASE light) by an optical amplifier arranged in an optical transmission path, and to prevent the occurrences of optical surges in an optical amplifier due to abrupt light input.
  • the reflect surface angles of the mirror devices 114 a can be set with respect to not only the X axis but the Y axis.
  • region St Shutter movement region
  • the collimators 111 - 2 and 111 - 3 which are output destination (see return light indicated by the broken line in FIG. 22 ).
  • Patent Document 2 Japanese Patent Application Laid-Open No. 2006-276487
  • Patent Document 3 Japanese Patent Application Laid-Open No. 2003-215645
  • Patent Document 4 Japanese Patent Application Laid-Open No. HEI 2-024635
  • the reflection surface angle of the movable mirror array 114 included in the above-described optical switch 110 shown in the above-described FIG. 20 and FIG. 21 is variably changed in response to a physical external force such as mechanical, opto-electrical, or opto-magnetic one, and there exists a certain disorder occurrence rate.
  • a physical external force such as mechanical, opto-electrical, or opto-magnetic one
  • the optical switch 110 is applied to the above-described wavelength multiplex OADM 100 or the like, the above-described redundant operation such as path switching is performed. At that time, standby optical ports and wavelength channels need to be switched in high-speed at the time of occurrence of disorder.
  • the optical switch when a wavelength-selective optical switch is applied to a wavelength multiplex OADM device 100 or the like, as preventive measures at the time of the above-mentioned occurrence of disorder, the optical switch itself is desirable to supervise that it has sufficient switching ability even during standby (that is, at the time not in operation), and also to always perform detect ion of disorders.
  • one object of the present invention is to make it possible to supervise the performance of optical switching in the standby channels or to detect disorder of optical switch constructions.
  • Another object of the invention is to monitor standby light of a wavelength not to be output for the purpose of improving the usefulness as an optical switch.
  • an optical switch having the following features.
  • an optical switch adapted to switch an optical path of a light beam from m (m is a natural number) optical input port to n (n is a natural number) optical output port(s) by the unit of wavelength.
  • the optical switch comprises: a collimator unit which makes the light from the optical input port parallel light; an optical splitter which splits the light from the collimator unit; a light gathering unit which gathers the light beams, which have been split by the optical splitter, for each wavelength; a rotatable mirror which is installed to individually reflect light beams of individual wavelengths, which have been gathered by the light-gathering unit, and whose reflect surface angle is set by rotation.
  • the collimator, the optical splitter, the focusing unit, and the rotatable mirror form a round optical path between the optical input port and the optical output port.
  • the optical switch further comprises a mirror angle control unit which controls a reflection surface angle of the rotatable mirror for each wavelength to switch ON/OFF of the light beam coupling to the optical output port for each wavelength reflected, and determine an optical output port position outputting light beams of the reflected wavelengths; and a monitor unit, installed on a return path of a light beam, which makes the optical coupling to the output port OFF.
  • the rotatable mirror has a plurality of rotation axes
  • the mirror angle controlling unit controls an angle of one of the rotation axes for the rotatable mirrors for each light beam, and switches ON/OFF of optical coupling to an optical port of the light beams of wavelengths reflected, the mirror angle controlling unit controlling an angle of one of the other axis of the rotatable mirror for each wavelength of the light beam, and determines optical output port positions to which the light beams of each wavelength reflected are output.
  • the mirror angle controlling unit includes: a movement operation giving unit which gives a cyclic movement of an angle of the one or said the other rotation axis so that an orbit of a light beam of a wavelength at which optical coupling to the optical output port is made OFF; and a supervisory unit which supervises the movement state of a rotatable mirror which reflects a light beam of the wavelength whose optical coupling to the optical output port is made OFF based on the amplitude or the frequency monitored by the monitoring unit due to a movement operation given by the movement operation giving unit.
  • the mirror angle controlling unit includes: a movement operation giving unit which moves the angle of said the one or said the other one of mirrors with respect to said the one or said the other rotation angle, so that the orbit of the light beam whose optical coupling to the output port is made OFF is moved; and the monitor unit includes: a photoreceptor element pair made of two photoreceptor elements arranged so that the sensitivities of each photoreceptor element partially overlap along the movement direction of the orbit of a light beam which is given from the movement operation giving unit.
  • the optical switch further comprises a monitoring unit, which detects an amount of control by the mirror angle controlling unit, when the reception sensitivity overlaps the reception sensitivity with movement operation given by the movement operation giving unit, and which monitors the operation state of the rotatable mirror for a light beam of a wavelength whose optical coupling to the optical output port is made OFF.
  • the movement operation giving unit moves the angle of a rotatable mirror with respect to one wavelength, out of the plurality of wavelengths to be supervised is moved, and the supervisory unit performs the above mentioned supervisory, and the movement giving unit and the operation monitoring unit sequentially switches the rotatable mirrors with respect to a wavelength to be monitored.
  • the monitoring unit includes a plurality of photoreception elements arranged in parallel in the optical output port.
  • the monitoring unit includes the number of photoreception elements corresponding to the number of optical output ports.
  • the monitoring unit includes the number of photoreception elements corresponding to the number of wavelengths which are arranged in parallel in the optical output port, to which the output destination is switchable.
  • the movement operation giving unit and the supervisory unit individually associate the rotatable mirrors of the plurality of wavelengths to be supervised with the photoreceptor elements, thereby supervising the movement state of rotatable mirrors of a plurality of wavelengths, and sequentially switch the association of the rotatable mirrors of the plurality of wavelengths with the photoreceptor element.
  • photoreceptor element pairs each composed of two photoreceptor elements, are arranged in parallel with the optical output port, the number of photoreceptor element pairs being arranged corresponding to the number of optical output ports.
  • reception element pairs each composed of two photoreceptor elements, are arranged in parallel in the optical port, and the number of the above photoreceptor elements corresponds to the number of wavelengths whose output destination is switchable.
  • the mirror angle controlling unit includes a movement operation giving unit which individually moves an angle of said the one of or said the other of light beam so that the orbit of the light beam whose optical coupling to the optical port is made to be OFF
  • the monitoring unit includes at least three photoreception element pairs arranged so that the reception sensitivities partially overlap in the at least two directions of the orbit of an optical beam given by the movement operation giving unit
  • the supervisory unit specifies a light beam position at which the reception sensitivities overlap along with a movement operation given by the movement operation giving unit, and individually supervises an operation state of said the one and said the other rotation axis in a rotation mirror which reflects a light beam of the wavelength whose optical coupling is made to be OFF, on the basis of the amount of controlling at the mirror angle controlling unit.
  • the monitor unit includes at least three photoreception element groups arranged in parallel in the optical port.
  • a plurality of photoreceptor element groups are arranged in parallel in the optical output port in the number corresponding to the number of optical output ports.
  • a plurality of photoreceptor element groups are arranged in the number corresponding to the number of wavelengths whose output destination is switchable.
  • the movement operation giving unit and the supervisory unit when a plurality of wavelengths whose optical coupling are made to be OFF, associate rotation mirrors with the photoreception element groups individually, thereby supervising the state of rotatable mirrors at a plurality of wavelengths, while by means of associating rotatable mirrors and the photoreceptor element individually, the movement operation giving unit and the supervisory unit sequentially switch the association of the rotatable mirrors of the plurality wavelengths to be supervised with photoreceptor element.
  • the mirror angle controlling unit controls the angle of the rotatable mirror so that the mirror angle controlling unit makes optical coupling ON about an optical beam of the wavelength in operation, and makes optical coupling OFF about an optical beam of the wavelength not in operation including natural radiation light
  • the monitoring unit monitors light beams whose optical coupling is made OFF of wavelengths not in use including the natural radiation light
  • the optical switch comprises a supervisory unit which supervises the movement state of the rotatable mirror, to which a light beam of the wavelength not in operation is reflected.
  • an optical amplifier which amplifies an input signal light together with natural radiation light is arranged before the optical input port.
  • a light input signal whose optical coupling to the optical output port is made OFF is detected based on the monitoring result by the monitoring unit.
  • the present invention is advantageous in that the usefulness as an optical switch is improved.
  • the present invention is advantageous in that the reliability in operation is improved.
  • FIG. 1 is a diagrammatic perspective view showing an optical switch according to a first embodiment of the present invention
  • FIG. 2 is a diagram showing an optical switching node to which an optical switch of the first embodiment is applied;
  • FIG. 3 , FIG. 4 , FIG. 5( a ) through FIG. 5( c ), and FIG. 6( a ) through FIG. 6( e ) each are diagrams for describing important constructions and operations of the optical switch according to the first embodiment
  • FIG. 7 is a flowchart for describing an operation of the optical switch according to the first embodiment
  • FIG. 8 is an diagram showing an optical switch according to a second embodiment of the present invention.
  • FIG. 9( a ) through FIG. 9( c ) each are diagrams for describing important constructions and operations of the optical switch according to the second embodiment
  • FIG. 10( a ) through FIG. 10( c ) each are diagrams for describing an operation of an optical switch according to the second embodiment
  • FIG. 11 is a flowchart for describing an operation of an optical switch according to the second embodiment
  • FIG. 12( a ) and FIG. 12( b ) both are a modified examples of an optical switch according to the second embodiment
  • FIG. 13 is a diagram for describing a third embodiment of the present invention.
  • FIG. 14 is a diagram showing the third embodiment of the present invention.
  • FIG. 15 is a diagram for describing a fourth embodiment of the present invention.
  • FIG. 16( a ) through FIG. 16( c ) each are diagrams for describing an operation of the fourth embodiment of the present invention.
  • FIG. 17 is a diagram for describing a fifth embodiment of the present invention.
  • FIG. 18 is a diagram for describing an operation of the fifth embodiment
  • FIG. 19 is a diagram showing previous technology
  • FIG. 20 is a diagram showing previous technology
  • FIG. 21 is a diagram showing previous technology
  • FIG. 22 is a diagram showing previous technology
  • FIG. 1 is a diagrammatic perspective view showing a wavelength-selective type optical switch 1 according to the first embodiment.
  • the optical switch 1 is applied to, for example, an optical switch node 10 arranged on an optical transmission path as shown in FIG. 2 .
  • This optical switch node 10 has an optical switch 1 according to the first embodiment, a pre-amplifier 11 on the upstream side of the optical switch 1 , and a post-amplifier 12 on the downstream side of the optical switch 1 .
  • reference character 13 indicates a splitter which takes out a part of a light signal output from the optical switch 1
  • reference character 14 indicates a spectrum monitor which performs spectrum analysis of an output of the optical switch 1 based on an optical signal taken out by the splitter 13 .
  • a light signal propagated through the transmission path and attenuated is amplified by a pre-amplifier 11 of the optical switch node 10 .
  • the optical spectrum of a light signal at the time point at which the light signal is input to the pre-amplifier 11 is as shown as A 1 in FIG. 2 .
  • the optical spectrum of a light signal at the time point at which the light signal is output from the pre-amplifier 11 is as shown as B 1 in FIG. 2 . That is, not only light of signal light wavelength band ⁇ 1 through ⁇ 3 but also natural radiation light (“standby ch ASE component”) including a wavelength component of the standby channel is optically amplified.
  • the optical switch 1 performs shielding processing to an optical component of the standby channel as shown in FIG. 22 .
  • the optical spectrum at the optical switch 1 becomes as shown by C 1 of FIG. 2 . That is, a standby channel component is removed (an “ASE component which is removed by the optical switch shutter”), and wavelength band spectrum of the in-service channels of ⁇ 1 through ⁇ 3 only pass through.
  • an optical signal output from the optical switch 1 is amplified by the post-amplifier 12 , and then output to the transmission path.
  • the optical switch 1 is capable of switching light beams from m (m is a natural number) light ports into n (n is a natural number) by the unit of wavelength.
  • light output ports for one input port is set to be m 1 (m 1 is a natural number greater than four).
  • an input optical fiber 21 having an end surface 21 a which is an optical input port and an output optical fiber 22 having an optical output port 22 a are arranged so that end surfaces 21 a and 22 a face in the same direction.
  • the optical switch 1 with respect to light of wavelength channel in-service, introduces light radiated from the end surface 21 a to an output optical fiber 22 to which light should be output.
  • light of wavelength standby
  • it can be removed at a output stage as described above. At that time, in the optical switch 1 of the first embodiment, it is possible to monitor a standby channel component to be removed at the output stage.
  • the optical switch 1 has a collimator 2 , a beam enlarging element 3 , an optical splitter element 4 , a lens 5 , and a movable mirror array 6 .
  • a go and return optical path is installed between the end surface 21 a of the end portion 21 a of the input fiber 21 which serves as an optical input port and the end portion 22 a of the output optical fiber 22 which serves as an optical output port.
  • the optical switch 1 has a driver 7 which activates the movable mirror array 6 , a monitor unit (photoreceptor element unit) 8 , and a controlling unit 9 .
  • the collimator 2 outputs light of the “go” path from the above-described input optical fiber 21 to the beam enlarging element 3 at a later stage as collimate light, and couples collimate light of an in-service channel from the beam enlarging element 3 .
  • a collimate lens 2 a arranged on an optical axis between the optical fibers 21 and 22 and the beam enlarging element 3 .
  • the beam enlarging element 3 outputs collimate light through the go optical path from the collimator 2 to the optical splitter element 4 as light having a beam shape spreading in the X axis direction in FIG. 1 .
  • the beam enlarging element 3 outputs light through the return path from the optical splitter element 4 as collimate light whose width is reduced, which light has been spread in the X direction.
  • the beam enlarging element 3 is made of a pair of lenses as shown in FIG. 1 . Accordingly, the above-described collimator 2 and the beam enlarging element 3 construct a collimate unit which makes light from the light input port into collimate light.
  • the optical splitter element 4 splits the collimate light through the go path from the beam enlarging element 3 , and for each wavelength channel component, radiates to the lens 5 at different angles (spreading in the X axis in the drawing).
  • the optical splitter element 4 radiates light through the return path from the lens 5 to the beam enlarging element 3 at different angles for each wavelength channel.
  • the optical splitter element 4 is a light splitter unit which splits light from the collimator unit.
  • the lens 5 converts all the light beams which incident at different wavelengths for each light wavelength into collimate light beams, and light of each wavelength channel is input at a focus of different mirrors 6 a making the movable mirror array 6 . Further, light on the return path reflected by the mirror 6 a , which constructs movable mirror array 6 , is output to the optical splitter element 4 . Accordingly, the lens 5 serves as a light-gathering unit which collects light for each light beams, split by the splitter, for each wavelength.
  • the movable mirror array 6 is made of mirror 6 a arranged in the X axis at the position of focus point of the lens 5 (corresponding to light-splitting by the optical splitter element 4 ).
  • Each mirror 6 a individually reflects light of the wavelength channels ( ⁇ 1 through ⁇ 5 ) split by the optical splitter element 4 .
  • its reflect surface is rotatable with respect to the X axis and the Y axis. As a result, it is possible to set the reflection face angle independently with respect to the X axis and the Y axis.
  • mirror 6 a making the movable mirror array 6 are rotatable mirrors having multiple rotation axes arranged for individually reflecting light beams of different wavelengths focused by the focusing unit.
  • the each mirror 6 a making the movable mirror array 6 is capable of determining an output optical fiber 22 to which coupling is performed by setting the tilt angle ⁇ x with respect to the X axis. That is, if the rotation control amount with respect to the Y axis is 0 degree, the light reflected by the mirror 6 a is coupled to the output optical fiber 22 which depends on the X axis angle of the mirror 6 a by way of the lens 5 , the optical splitter element 4 , the beam enlarging element 3 , and the collimator 2 .
  • each mirror 6 a making the movable mirror array 6 the reflect face angle ⁇ y with respect to the Y axis is tilted, and hereby the light reflected by the mirror 6 a is radiated to the shutter operation region, in which photoreceptor element 81 making the monitor unit 8 is arranged, and deviated from the optical path to the collimator 2 , which is coupled to the output optical fiber 22 , through the lens 5 , the optical splitter element 4 , the beam enlarging element 3 .
  • the optical switch 1 which is applied to the optical switch node 10 , light of in-service wavelength channel is coupled to the output optical fiber 22 with the reflection angle ⁇ y being substantially 0 degree.
  • light of the standby wavelength channel is controlled to rotate so that the reflection surface angle ⁇ y is tilted with respect to the Y axis, by means of an shutter operation, as shown in return path light R 1 .
  • the standby light is radiated to a shutter operation region St in which photodiode 81 is arranged.
  • the optical level to be coupled to the output optical fiber 22 is attenuated to a target level having been set.
  • the driver 7 is subjected to driving control by the control unit 9 (described later).
  • the driver 7 activates the movable mirror array 6 . That is, by means of external forces generated by activation of the movable mirror array 6 by the driver 7 , each mirror 6 a is tilted by the angle having been set.
  • the monitoring unit 8 is arranged on the return path of a light beam whose optical coupling to the optical output port is made to be OFF, and monitors a light beam whose optical coupling to the optical output port is made to be OFF.
  • the collimator 2 is made of photodiode 81 , as a photoreceptor element which outputs an electric signal corresponding to the light reception amount.
  • the controlling unit 9 performs activating control to the driver 7 .
  • the driver 7 is activated to radiate the light to the shutter operation region St.
  • the above-described controlling unit 9 cooperates with the driver 7 , thereby controlling a light beam which is reflected with respect to the Y axis, as one rotation axis of the mirror 6 a , and switches ON/OFF of the optical coupling to the optical output port for the light beam for each reflected wavelength, and controls an angle of the X axis, as the other rotation axis, with respect to the X axis which is another rotation axis of the mirror 6 a , and constructs a mirror angle controlling unit which determines the optical output port positions from which light beams of the reflected wavelengths are output.
  • the controlling unit 9 which serves as a mirror angel controlling unit, makes optical coupling ON with respect to the light beam of a signal light wavelength in service.
  • the mirror 6 a is set to make optical coupling to the optical output port OFF.
  • the controlling unit 9 has an optical current detection circuit 9 a , an AD converter 9 b , a temperature sensor 9 c , a control/compare calculating unit 9 d , and a DA converter 9 e .
  • the optical current detection circuit 9 a detects an electric signal corresponding to the light amount received by the photoreceptor element 81 , and for example, it is made of an amplifier, etc.
  • the AD converter 9 b converts an electric current signal value (analogue signal) detected by the optical current detection circuit 9 a into a digital signal.
  • control/compare calculating unit 9 d controls setting of the above-described tilt angle of each of the mirror 6 a with respect to the X axis, thereby regulating connection of the optical input/output port of the in-service wavelength channels.
  • control/compare calculating unit 9 d performs controls the tilt angle with respect to the Y axis for each mirror 6 a , thereby radiating light of the in-service wavelength channels to the coupling region of the collimator 2 which passes to the optical output port.
  • light of out-of-service wavelengths is radiated to the shutter movement region St.
  • the mirror 6 a which reflects standby channel light which is radiated to the shutter movement region St, is controlled so as to make a dithering operation in which the mirror 6 a rotate alternatively in two opposite directions or cyclically with respect to the X axis as shown in FIG. 4 byway of setting control of the tilt angles. That is, the light axis of light on the return path which reflects to the mirror 6 a which has made a dithering movement under control of the control/compare calculating unit 9 d cyclically varies between the optical axes R 11 and R 12 shown in FIG. 4 .
  • FIG. 5( a ) through FIG. 5( c ) are diameters for describing relative variation of the light amount received by the photoreceptor element 81 by means of cyclic variation of the optical axis together with the arrangement relationship between the collimator 2 and the photoreceptor element 81 .
  • FIG. 5( a ) through FIG. 5( c ) as an example, three collimators 2 are arranged in the collimator coupling region C as collimator 2 , and three collimators 2 are arranged in the collimator coupling region C.
  • a photoreceptor element 81 is installed in the collimator coupling region C as the collimators 2 to be coupled to the optical input/output port.
  • FIG. 5( a ) through FIG. 5( c ) never indicate that the present invention is limited in the number of wavelength channels.
  • wavelength channels ⁇ 1 through ⁇ 3 in-service are coupled to the collimators 2 which serve as port # 1 through # 3 .
  • Standby wavelength channels ⁇ 4 and ⁇ 5 are input to the shutter movement region St.
  • the light on the return path is shut out from the collimator coupling region C by means of rotation of the reflection surface with respect to the Y axis of the mirror 6 a .
  • the shutter movement region St is arranged at a position deviated from the collimator coupling region C with respect to the X axis.
  • the standby wavelength channel ⁇ 4 is subjected to dithering operation with respect to the X axis, so that the position of light input to the shutter movement region St can be made up and down along the Y axis with the photoreception position as reference position.
  • the light position to which light is input to the shutter movement region St can be moved from side to side along with the X axis with the photoreception position of the photoreceptor element 81 as a reference.
  • wavelength channel ⁇ 4 is firstly subjected to dithering, thereby making the light of ⁇ 4 to be an object of supervising.
  • light of another wavelength of channel ⁇ 5 is input to a retraction area St 1 which is deviated from the reception light position pf the photoreceptor element 81 of the shutter operation region St.
  • the light of wavelength channel ⁇ 5 is subjected to dithering to switch light of ⁇ 5 to the monitoring object.
  • light of the wavelength channel ⁇ 4 is input to the retraction area St 1 .
  • wavelength channels to be supervised are changed at a predetermined cyclic duration. As a result, it becomes possible to supervise deterioration of transient response of the mirror 6 a in particular.
  • FIG. 6( a ) through FIG. 6( e ) are diagrams describing that the possibility of supervising deterioration of transient response of the wavelength channel, by dithering the mirror 6 a to be monitored.
  • the control/compare calculating unit 9 d Through control by the control/compare calculating unit 9 d , if the frequency of the dithering operation is given as “f”, the optical current amplitude by the photoreceptor element 81 is changed, as shown in FIG. 6( a ) according to the dithering frequency.
  • the mirror 6 a makes resonant movement.
  • the angle of fluctuation is considered to become the maximum. That is, as shown in FIG. 6( d ), the optical current amplitude Apd of the photoreceptor element 81 takes the maximum value.
  • f 0 at this moment can be resonance frequency with respect to the X axis of mirror 6 ( a ).
  • the mirror 6 a cannot support the frequency (modulated frequency) of an activating signal.
  • the deviate angle of the mirror 6 a becomes also small, and as shown in FIG. 6( e ), optical current amplitude Apd in the photoreceptor element 81 becomes smaller than the above-described cases FIG. 6( b ) through FIG. 6( d ).
  • the control/compare calculating unit 9 d holds the optical current amplitude value at the photoreceptor element 81 corresponding to the modulation frequency at the time of manufacturing of the movable mirror array 6 , for example.
  • the control/compare calculating unit 9 d holds the optical current amplitude value at the photoreceptor element 81 corresponding to the modulation frequency at the time of manufacturing of the movable mirror array 6 , for example.
  • control/compare calculating unit 9 d the DA converter 9 e , and the driver 7 composing the controlling unit 9 construct a mobile movement giving unit which varies the angle of the mirror 6 a with respect to the X axis and the Y axis in the mirror 6 a so that the orbit of a light beam, whose optical coupling to the optical output port is OFF, is cyclically moved to the optical output port becomes OFF.
  • the optical current detection circuit 9 a , the AD converter 9 b , and the control/compare calculating unit 9 d which make the controlling unit 9 , construct a monitoring unit which monitors the movement state of the mirror to which a light beam of the out-of-service light wavelength is reflected based on the monitoring result obtained at the monitoring unit 8 .
  • this control/compare calculating unit 9 d as a monitoring unit, is capable of monitoring the operation state of the mirror 6 a which reflect light beams of out-of-service signal light wavelengths on the basis of the amplitude of light amount changes which are monitored by the photoreceptor element 81 based on the movement operation given by the movement operation giving unit.
  • the control/compare calculating unit 9 d decides a resonance point based on the optical current amplitude value input through the optical current detection circuit 9 a and the AD converter 9 b .
  • the control/compare calculating unit 9 d is capable of taking into the frequency of the direct reception signal to monitor the operation state of the mirror 6 a.
  • control/compare calculating unit 9 d in consideration of the fact that the response characteristic of the mirror 6 a depends on the ambient temperature, is capable of controlling the driver 7 in order to give the driving signal corresponding to the ambient temperature of the mirror 6 a detected by the temperature sensor 9 c.
  • standby channels not in service direct all to the shutter movement region [see St of FIG. 3 , FIG. 5( a ) through FIG. 5( c )] to prevent unnecessary optical coupling to an channel (step A 1 ), and this mirror movement region holds standby channels (step A 2 ).
  • the monitoring object is determined as the mirror 6 a which reflects an optical beam of wavelength ⁇ n.
  • an X axis activating voltage Vx(n) for X axis rotation and a Y-axis activating voltage Yy(n) for Y axis rotation, as activating signals, are adjusted (step A 3 ).
  • Vx(n) and Vy(n) can be adjusted at the time they are manufactured beforehand to make coupling to the photoreceptor element optimal and can be stored in a memory or the like.
  • the movable mirror 6 a which area to be monitored make a dithering operation to detect the resonance frequency f 0 of the mirror 6 a .
  • the frequency in which a dithering operation is made is an appropriate range which is across f 0 , from a frequency lower than a considerable resonance frequency f 0 to a frequency higher than f 0 , and it is varied by an appropriated step value.
  • modulation amplitude is set as an appropriate range such that an AD converter 9 b (see FIG. 2 ), which performs AD conversion of the photoreceptor element 81 and optical current, is not saturated and effects of noise level do not exist.
  • control/compare calculating unit 9 d of the controlling unit 9 to perform dithering reflection surface angle with respect to the X axis, while controlling the driver 7 so that starting from a frequency component value which is given to Vx(n) that is sufficiently (fxmin) smaller than an assumed frequency component, and so that increase by a step value (step A 4 ).
  • Such calculation of optical current amplitude is sequentially continued by adding a step value step until fxmax, which is a sufficiently high frequency across f 0 , is obtained (NO route from step A 7 to step A 8 , from step A 8 through step A 4 through step A 6 ).
  • the dithering frequency (modulation frequency) f 0 xb ( n ) at the time the optical current amplitude Apd(n) becomes the maximum is detected (from YES route of step A 7 through step A 9 ).
  • the dithering frequency f 0 xb ( n ) given to the mirror 6 a at the time the optical current amplitude detected by the photoreceptor element 81 becomes the maximum is a substantial resonance frequency of the movable mirror 6 a.
  • the measured resonance frequency f 0 xb ( n ) detected by the above described operation is compared with the initial resonance frequency f 0 xa ( n ), which is tested at the time of shipping and stored in the memory f 0 xa ( n ), to compare to know whether to be the same as the variation threshold value fc, which has been determined beforehand. More specifically, a difference ⁇ f 0 xb ( n ) between the detected resonance frequency f 0 xb ( n ) and the resonance frequency f 0 xa ( n ) of the mirror 6 a at the time of shipping of the optical switch 1 is calculated (step A 10 ).
  • step A 11 Depending on whether this difference ⁇ f 0 x ( n ) is smaller or not than a regulation upper limit value fxc, it is evaluated whether or not ⁇ f 0 x ( n ) is within a regulation region (step A 11 ).
  • the control/compare calculating unit 9 d outputs an alarm flag meaning that any disorder or deterioration has occurred in an upper system not illustrated (from NO route of step A 11 to step A 12 ).
  • f 0 x ( n ) is within the reguration region (YES rout of step A 11 ), as a result of dithering with respect to the X axis, it is possible to supervise by dithering with respect to the above-mentioned Y axis. More specifically, similar to dithering of the reflect surface angle with respect to the X axis, the driving voltage Vy(n) is subjected to dithering as to reflection surface angle with respect to the Y axis.
  • the resonance frequency f 0 yb ( n ) is obtained (step A 13 ), and it is evaluated whether the obtained frequency f 0 yb ( n ) is within the regulation (see from step A 14 , steps A 10 and A 11 in a case of X-axis dithering).
  • the monitoring unit 8 and the controlling unit 9 supervise the performance of standby optical switches to detect mechanical or electric deterioration of standby channels which are not in service, without effecting in-service channels. Thus, it is possible to improve reliability of the optical switch 1 in service.
  • FIG. 8 is a diagram showing the construction of an important part of an optical switch 30 according to a second embodiment of the invention, and corresponds to a diagram of a view direction shown in FIG. 4 of the optical switch 1 according to the first embodiment.
  • An optical switch 30 shown in FIG.8 as in the case of the optical switch 1 according to the first embodiment, functions as a wavelength-selective optical switch.
  • the optical switch 30 as in the case of the optical switch 1 , basically has collimators which are not illustrated and similar to those of the optical switch 1 , an expander, a photoreceptor element 4 , a lens 5 , a movable mirror array 6 , and a driver 7 , it is different from the optical switch 1 in that it has a monitor unit 38 and a controlling unit 39 having a different construction of those of the optical switch 1 .
  • items indicated by the same reference characters are approximately similar to those of FIG. 4 .
  • the optical switch 30 according to the second embodiment, different from the above-described first embodiment, has collimators 2 arranges in parallel, and has a photoreceptor element pair 38 including two photoreceptor elements 381 and 382 along the Y axis arranged in parallel with the collimators 2 . These two photoreceptor elements 381 and 382 arranged so that photoreceptive sensitivities overlap along the movement direction of a light beam orbit given by the controlling unit 39 (described later) and the driver 7 .
  • the controlling unit 39 have two optical electric current detection circuits 391 a and 392 s fro detecting received optical current from the above photoreceptor elements 381 and 382 , and each also have AD converters 391 b and 392 b which perform A/D (analogue/digital) conversion of signals from the electric current detection circuits 391 a and 392 a.
  • control/compare calculating unit 39 d together with the above DA converter 9 e and the driver 7 , performs setting controls of the reflection surface angle of the mirror 6 a of the movable mirror array 6 , and function as a mirror angle control unit. It also functions as a movement operation giving unit which moves the reflection face angle of the mirror 6 a with respect to the X axis and the Y axis.
  • control/compare calculating unit 39 d constructs a monitoring unit, together with the above described optical current detecting circuits 391 a and 392 a . That is, the above-described optical current detecting circuits 391 a and 392 a , the AD converters 391 b and 392 b , and the control/compare calculating unit 39 d cooperate to detect the control amount for obtaining the angle of the mirror 6 a at the time the photoreception sensitivities overlap resulting from the movement operation given by the driver 7 on the basis of a signal corresponding to the light amount received by the photoreceptor element pair 38 , and monitors rotation mirrors condition which reflect light beams of wavelengths whose optical coupling to the optical output port is made to be OFF.
  • FIG. 9( a ) through FIG. 9( c ) each are diagrams for describing an arrangement relationship of the collimators 2 and photoreceptor element pair 38 , and also movement of light input to the shutter movement region St.
  • FIG. 9( a ) through FIG. 9( c ) to monitor deterioration of static characteristics of the mirror 6 a of the movable mirror array 6 , two photoreceptor elements 381 and 382 are provided.
  • the number of ports is three, but the number of ports should by no means be limited.
  • the collimators 2 are arranged at positions at which each collimator 2 is coupled to each optical input output port within the collimator coupling region C.
  • the two photoreceptor elements 381 and 382 arranged in parallel with the collimators 2 within the shutter movement region St in which coupling to the collimators 2 is made to be OFF.
  • wavelengths channels ⁇ 1 through ⁇ 3 in service are coupled to the collimators 2 as ports # 1 through # 3 , respectively.
  • the standby wavelengths channels ⁇ 4 and ⁇ 5 are input to the shutter movement region St.
  • the mirror 6 a corresponding to ⁇ 4 is rotated in the direction of the X axis, as shown in FIG. 8 and FIG. 9( b ), so that the incident position of the return light of the wavelength ⁇ 4 input to the shutter movement region St is across the photoreceptor elements 381 and 382 in the illustrated arrow direction AR.
  • the wavelength channel ⁇ 5 is input to the save region St 1 which saves input to the photoreceptor elements 381 and 382 .
  • control/compare calculating unit 39 d activates the driver 7 through the DA converter 9 e , thereby rotating the mirror 6 a for the standby channel ⁇ 4 with respect to the X axis.
  • return light R 2 shown by the solid line in FIG. 8 moves up and down like return light R 3 and R 4 which are indicated by the broken lines in FIG. 8 .
  • the control/compare calculating unit 39 d can deviate an activating light value which is that when the mirror 6 a is at a reference angle.
  • optical currents from the photoreceptor elements 381 and 382 detected by the optical current detecting circuits 391 a and 392 a have relationships shown in FIG. 10( a ) and FIG. 10( b ), respectively.
  • the install interval of the photoreceptor elements 381 and 382 is adjusted, as shown in FIG. 10(C) , at a certain driving voltage (reference driving voltage V), the detection values of optical currents from the photoreceptor elements 381 and 382 overlap.
  • the optical current detection values from the photoreceptor elements 381 and 382 overlap.
  • the control/compare calculating unit 39 d takes in the detection electric current value from the AD converters 391 b and 392 b , and deviates a reference driving voltage V 0 with respect to the mirror 6 a when the difference between detection electric current values takes zero.
  • driving current values from the photoreceptor elements 381 and 382 of when the optical current detection values overlap are measured at the time of shipping, and stored in a memory or the like provided inside the control/compare calculating unit 39 d.
  • control/compare calculating unit 39 d measures the above-mentioned reference driving voltage V 0 by means of activating the monitoring operation at appropriate cycles, and compares it with data in the memory of the time of a test. At that time, when the comparison result exceeds a predetermined threshold value, the control/compare calculating unit 39 d is capable of outputting an alarm to the upper system as disorder.
  • control can be performed in such a manner that the deterioration detect ion operation is immediately halted, and a target connection is performed or a control is performed so that such a deterioration detection operation is performed only when an instruction is given from the upper system.
  • step B 1 all the standby channels not in service are directed to the shutter movement region [see St of FIG. 10( a ) through FIG. 10( c )] (step B 1 ), and standby channels are held in this shutter movement region (step B 2 ).
  • the monitoring object is a mirror 6 a reflecting an optical beam of wavelength ⁇ n
  • the voltage Vx 1 ( n ) for the X axis rotation and the voltage Vy(n) for the Y axis rotation, as driving signals, are adjusted so that coupling to one photoreceptor element 381 reflected from the mirror 6 a becomes optimal (step B 3 ).
  • control/compare calculating unit 39 d activates the driver 7 through the DA converter 9 e , thereby increasing an activating voltage Vx(n) output from the driver 7 for rotation of the mirror 6 a with respect to the X axis by increasing from the above-mentioned Vx 1 ( n ) by an increment voltage value Vstep.
  • the mirror 6 a is rotated to move the incident position of light of ⁇ 4 which is input to the shutter movement region St to the direction for optical coupling to the photoreceptor element 382 (step B 4 ).
  • control/compare calculating unit 39 d evaluates whether or not optical current detection values Ipd 1 and Ipd 2 from the photoreceptor elements 381 and 382 (step B 5 ), from which it is evaluated whether or not the detection values of optical current from the photoreceptor elements 381 and 382 (step B 7 ) overlap.
  • step B 9 a difference ⁇ Vx(n) between these Vxb(n) and Vxa(n) is obtained (step B 9 ), and evaluates whether or not the ⁇ Vx(n) becomes not greater than the regulation Vc, thereby evaluating whether or not ⁇ Vx(n) is within the regulation range (step B 10 ).
  • control/compare calculating unit 39 d supervises the angle of the mirror 6 a of one wavelength, which is a supervising object out of the multiple wavelengths, and also switches rotatable mirrors of wavelengths which are object of supervising.
  • the monitoring unit 38 and the controlling unit 39 monitor the performance of optical switching in the standby channel, and thereby, it is possible to detect the characteristic changes such as the mechanical and electrical deterioration of the standby channels not in service without influencing channels in service, so that the reliability of the optical switch 1 in service is improved.
  • movement of an incident position to the shutter movement region St does not need to and fro movement, so that it is possible to simplify the control of a mirror 6 a , thereby reducing load to the mirror 6 a for supervising. As a result, it can be expected that disorder detection processing is sped up.
  • the photoreceptor element pair 38 has two photoreceptor elements along the direction of the arrangement direction of the collimator 2 (Y axis direction).
  • two photoreceptor elements can be arranged along the X axis, and with respect to the mirror 6 a to be supervised, the movement of an incident position to the shutter movement region St can be performed along the X axis direction. As a result, it becomes possible to supervise the movement state in the rotation direction with respect to I axis of the mirror 6 a.
  • a photoreceptor element 383 arranged in the direction along the X axis can be provided.
  • FIG. 14 is a diagram showing a third embodiment of the present invention.
  • the optical switch 1 has one photoreceptor element 81 in the shutter movement region St.
  • photoreceptor elements 81 through 8 n in association with arrangement of multiple photoreceptor elements, in particular, each output port (or collimator coupling to each input/output port), photoreceptor elements 81 through 8 n (in FIG. 14 , five photoreceptors 81 through 85 ) equal in number of the ports can be provided.
  • multiple optical current detecting circuits and AD converters equal in number of the photoreceptor elements as in the case of the second embodiment can be provided.
  • the other constructions can be the same as those in the first embodiment.
  • collimators 2 corresponding to the optical output ports # 1 through # 5 are provided for the collimator coupling region C, but this does not mean that the number of optical input/output ports is limited.
  • the tilt angles of the mirror 6 a (see FIG. 1 ) composing the movable mirror array 6 are changed in accordance with an activating voltage, as shown in FIG. 13 .
  • an activating voltage signal necessary for the mirror 6 a becomes the minimum voltage V # 5 .
  • the collimator 2 coupled to the return light reflected by the mirror 6 a corresponds to the port # 4 through the port # 1 at the positions apart from the port 5 #, the tilt angle necessary for the mirror 6 a becomes larger, and the corresponding driving voltage signals also become larger (V # 4 through V # 1 ).
  • wavelengths coupled to the photoreceptor elements 81 through 85 provided corresponding to the ports # 1 through # 5 are allocated by standby channel wavelengths, thereby monitoring the operation state of the corresponding mirror 6 a.
  • the similar dithering as in the case of the first embodiment is performed.
  • This makes it possible to supervise the mirror 6 a which reflects wavelength ⁇ 1 in a condition where coupling is performed to the port # 1 .
  • From then on by means of performing dithering in a condition where coupling is performed to the photoreceptor elements 82 through 85 , it is possible to supervise the operation state in a condition where coupling is performed to the ports # 2 through # 5 .
  • wavelengths to be coupled to the photoreceptor elements 81 through 85 are allocated one by one and performs supervising.
  • wavelength allocation to be coupled to the photoreceptor elements 81 through 85 at a fixed cycle is sequentially changed. As a result, it becomes possible to perform supervising of multiple standby channels to the corresponding ports # 1 through # 5 efficiently and accurately.
  • the tilt angles of the mirror 6 a are appropriately set to attempt to obtain a target optical coupling.
  • disorder in which the angle does not reach the target angle occurs is probable.
  • a construction for detecting disorder corresponding to each port makes it possible to detect disorder at angles coupling to all the optical ports for each mirror 6 a reflecting a wavelength channel.
  • photoreceptor elements of the number corresponding to the number of the optical output port are arranged in parallel with the optical output ports. As a result, it is possible to improve the accuracy of monitoring.
  • FIG. 15 is a diagram showing a fourth embodiment of the present invention.
  • the optical switch 30 has one photoreceptor element pair 38 (two photoreceptor elements 381 and 382 ) in the shutter movement region St.
  • multiple photoreceptor element pairs can be provided in parallel with the strain of the collimators 2 .
  • switchable (accommodated in the optical switch) photoreceptor element pairs 481 through 48 m of the number of wavelength channels (m wavelengths) can be provided, or as an modified example, those of the number of optical output ports can also be provided.
  • optical current detecting circuits and AD converters equal in number of photoreceptor elements can be provided, as in the case of the second embodiment. In this instance, the other constructions are similar to those of the second embodiment.
  • the reflection surface angles of the mirror 6 a can be set to receive light of wavelengths ⁇ 1 through ⁇ m.
  • the operation state of mirror 6 a is supervised by means of obtaining reference activating voltages Vx( 1 ) through Vx(m) based on optical current detection values from photoreceptor element pairs 481 thorugh 48 m.
  • wavelength channels input to the photoreceptor element pairs 481 through 48 m are fixed, relatively large load is applied to the mirror 6 a of the particular wavelength light, which mirror's rotation angle is made to be necessary to relatively enlarged.
  • the association between the wavelength channels to be supervised at a predetermined cycle and the photoreceptor element pairs 481 through 48 m are subjected to rotation for switching.
  • wavelength channels which are objects of monitoring using the photoreceptor element pairs 481 through 48 m are given as wavelengths ⁇ m, ⁇ 1 through ⁇ m- 1 , respectively.
  • wavelength channels which are objects of supervising in use of the photoreceptor element pairs 481 through 48 m are given as wavelengths ⁇ m, ⁇ 1 through ⁇ m- 2 , and from then on, frequencies are sequentially shifted one by one.
  • the similar advantages to those of the second embodiment are realized.
  • the photoreceptor element pairs 481 through 48 m of the number (m wavelengths) of switchable wavelength channels are provided, it becomes possible to always supervise disorder of all of the standby channels.
  • disorder detection in real time is realized, and it is possible to improve the reliability of the accuracy of disorder detection.
  • FIG. 17 is a diagram showing a fifth embodiment of the present invention.
  • photoreceptor element pairs 481 through 48 m each composed of two photoreceptor elements arranged in the direction along the arrangement of the collimators 2 , are arranged equal in number (m wavelengths) of switchable (accommodated in the optical switch) wavelength channels.
  • a monitoring unit 58 multiple photoreceptor element groups 581 through 58 m , each composed of three photoreceptor elements which are arranged as shown in the above-described FIG. 12( a ) and FIG. 12( b ), can be provided in parallel with the arrangement of the collimators 2 .
  • switchable (accommodated in the optical switch) photoreceptor element groups 581 through 58 m equal in number (m wavelengths) to the wavelength channels can be provided, or as a modified example, the optical output port-number of photoreceptor element groups 581 through 58 m cab be provided.
  • the number of photoreceptor elements composing each group and their arrangement should by no means be limited to the case of FIG. 17 , and it is possible, as appropriate, to change the number of photoreceptor elements arranged in parallel with the X axis into not smaller than three, for example.
  • multiple optical current detecting circuits and AD converters can be equal in number to the number of photoreceptor elements, as in the case of the second and the fourth embodiment.
  • the other construction is made to be the similar to the embodiment of the above-described FIG. 12( a ) and FIG. 12( b ).
  • reflection surface angles of the mirror 6 a are set so that the photoreceptor element groups 581 through 58 m receive light of wavelengths ⁇ 1 through ⁇ m, respectively.
  • reference activating voltages Vx( 1 ) through Vx(m) in a case (A) where the mirror 6 a are rotated with respect to the X axis are obtained, and the reference activating voltages Vy( 1 ) through Vy(m) of a case (B) where the mirror 6 a are rotated with respect to the Y axis are obtained.
  • the operation states of the mirror 6 a reflecting wavelength channels are simultaneously supervised.
  • wavelength channels input to the photoreceptor element groups 581 through 58 m are fixed, relatively large load is applied to a mirror 6 a of a certain wavelength channel whose rotation angle is made to be relatively large.
  • the association between the wavelength channel to be supervised at a predetermined cycle and the photoreceptor element groups 581 through 58 m are switched by rotation.
  • the wavelength channels to be monitored using the photoreceptor element groups 581 through 58 m are given as wavelengths ⁇ m, ⁇ 1 through ⁇ m- 1 , and wavelength channels to be supervised using the photoreceptor element groups 581 through 58 m shifted by one wavelength channel.
  • the wavelength channels to be supervised using the photoreceptor element groups 581 through 58 m are given as wavelengths ⁇ m- 1 , ⁇ m, and ⁇ 1 through ⁇ m- 2 . After then on, wavelength channels are sequentially shifted one by one.
  • photoreceptor element groups 581 through 58 m are provided equal in number to switchable wavelength channels (m wavelengths), it becomes possible to always supervise disorder of all the standby channels, so that it is possible to improve the reliability of disorder detection. Further, since it is possible to supervise the movement state of mirror 6 a with respect to the Y axis, the monitoring accuracy in real time is more improved.
  • a construction for supervising the operation state of the mirror 6 a for all the wavelength channels in rotation direction with respect to the X axis and the Y axis in addition to the construction of the above-described fifth embodiment, a construction is also applicable in which photoreceptor elements arranged in the shutter movement region St in two receptor element rows in parallel with the collimators 2 , and in one row, at least (the number of wavelength channels+1) ⁇ number of photoreceptor elements are arranged. In this case, monitoring of each wavelength channel is sequentially performed, and light of the adjacent wavelength channel is saved. Then, at rotation of association between the wavelength channels to be supervised and photoreceptor elements are supervised by shifting allocation by one step along the arrangement direction of the collimators 2 .
  • the control/compare calculating unit 9 d detects an optical current of the level corresponding to the input signal light based on the optical current from the AD converter 9 b , it is possible to detect a wavelength at which optical coupling to the optical output pot is made OFF, that is, the input signal light of the wavelength whose optical coupling to the optical output port, that is, to detect input of a signal light in standby of the wavelength, and then to notify the upper system of such.
  • a control/compare calculating unit supervises the presence or the absence of input to an optical port of the standby wavelength channel.
  • the mirror 6 a is moved at an appropriate cycle, thereby performing polling detection.
  • control/compare calculating unit specifies an optical port to which input is performed based on a movable mirror movement angle and the position of the detected photoreceptor element, and it is notified to the upper system. As a result, the usefulness as an optical switch is improved.

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US20140341583A1 (en) * 2010-07-26 2014-11-20 Ii-Iv Incorporated Reconfigurable Optical Add-Drop Multiplexer
US20130034353A1 (en) * 2011-08-02 2013-02-07 Fujitsu Limited Optical transmission device and optical transmission method
US9379839B2 (en) * 2011-08-02 2016-06-28 Fujitsu Limited Optical transmission device and optical transmission method

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